Our overall goal is to understand the mechanisms in the behavior of a relatively simple organism by genetic dissection. This is done by producing lesions with mutagenesis and analyzing the resultant effects on behavior, electrophysiology, ultrastructure, and the biochemistry of the system. The organism of choice is Paramecium tetraurelia. Using locomotion as the indicator of the state of the excitable membrane, mutants with defective ion "channels" or "gates" have been isolated and analyzed. We intend to continue this interdisciplinary research. Specifically, we proposed to study the patterns of ciliary membrane proteins by electrophoreses of purified ciliary membrane vesicles; to examine mutants or variants isolated in various ion-enrichment procedures; to test the isolated cilia for their integrity through osmotic swelling and shrinking, and test their excitability if they are sealed; and to examine the membrane mutants in our collection for their possible ultrastructural defects with the electron microscope.